Studies addressing the issue of some former addicts' abnormal responsivity to metyrapone testing, a hyperresponsivity which could be due to excessive amounts of the hypothalamic peptide hormone corticotropin releasing factor (CRF), are conducted in this project. CRF is given to recently abstinent cocaine addicts, subjects with other addictive diseases, and normal control subjects. Also, a withdrawal-like response to metyrapone testing observed in some former addicts is studied.